In most countries, breast cancer is the second most prevalent cancer to afflict women. Currently, abnormal breast tissue is detected by various methods, such as physical breast examination, mammography, ultrasound and other breast imaging methods.
In order to determine whether such abnormalities are benign or malignant, examination of the histopathology of the abnormal tissue is required. Therefore, a sample of the abnormal tissue is taken by biopsy and is analysed by microscopic evaluation.
At present, there are biopsy techniques that can be performed through a small incision in the affected breast, and which are therefore considered to be minimally invasive. Typically, a radiologist or surgeon removes a sample of breast tissue and sends it to a pathological laboratory for microscopic examination. Minimally invasive techniques for breast biopsy include fine needle aspiration (FNA), core needle biopsy, large core surgical (ABBI) and vacuum-assisted biopsy (Mammotome or MIBB).
Minimally invasive biopsies may use computer-generated images to locate breast abnormalities, including the use of x-ray and ultrasound generated images. By accurately pinpointing and mapping the area to be biopsied, a small sample can easily be taken from the abnormal tissue.
The existing biopsy methods are limited to one or at most a few sample removals, and are not designed, nor are intended, to perform surgical excision of the abnormality. In some cases the biopsy method is limited to the removal of just enough cells or fluid sufficient for pathological testing.
If the abnormality is confirmed to be cancerous, typically the abnormal tissue, as well as a surrounding margin of healthy tissue, is removed. Surgical methods typically involve either a lumpectomy, which involves removal of the abnormality and surrounding tissue while leaving the majority of the breast tissue intact, or a mastectomy, which involves removal of all or a large portion of the breast tissue. Surgical removal may be done in combination with other treatments, such as chemotherapy or radiation treatment.
The advent of screening mammography has led to a paradigm shift in the presentation of breast cancers, with a higher proportion of tumours diagnosed at an impalpable stage. These lesions are smaller in size, and breast conservation treatment would be appropriate for these cancers. Breast conservation therapy involves the removal of the cancer, together with a margin of surrounding normal tissue, followed by a secondary treatment as necessary.
Surgical methods typically require stitches to close the excision and can leave a scar, which may complicate the interpretation of follow up breast examinations; increase the chance of bleeding, and infection; and cause problems with wound healing. As well, there are mortality risks associated with the use of anaesthesia.
Clearly then, there is a need for minimally invasive surgical methods for effective removal of abnormal tissue from a breast.